According to the hotel page,
From April 7, 2014 through March 28, 2015, the Porto Paradiso Side of Tokyo DisneySea Hotel MiraCosta will be undergoing periodic renovations of the exterior walls. During this period, Guests may experience noise and the smell of paint.
A select number of rooms undergoing exterior renovations will be available for a discounted price.
Dates: April 7, 2014 through September 30, 2014
Prices: Value ¥30,900 / Regular ¥36,000 / Peak ¥41,200 / Top ¥46,300 (per room)
Room Type: Porto Paradiso Side
So it will be a great chance for those wanting to stay there, especially at this 'legend' view.